Unit heating ventilator



July 2, 1935. c. P. BRIDGES UNIT HEATING VENTILATOR Filed March 12, 1951 4 Sheets-Sheet l finial.-

July 2, 1935. c. P. BRIDGES UNIT HEATING VENTILATOR Filed March 12, 1951 4 Sheeis-Sheet 2 mNNm hm y 1935- c. P. BRIDGES UNIT HEATING VENTILATOR I 4 Sheets-Sheet 3 Filed March 12,

Jzveniqr c. P. BRIDGES 2,006,534

UNIT HEATING VENTILATOR July 2, 1935.

Filed March 12, 1931 4 Sheets-Sheet Fig. 7

fizventor Patented July 2, 1935 UNITED. STATES PATENT OFFICE A UN IT HEATING VENTILATOR Charles P. Bridges, Dedham, Mass, assignor to B. F. Sturtevant Company, Hyde Park, Mass, a corporation of Massachusetts Application March 12, 1931,.Serial No. 521,997

11 Claims. (Cl. 236-'-38) M The present inventionrelates generally to with certainty and accuracy to maintain the :desired conditions.

With these and other objects in View as will hereinafter be apparent to those skilled in the art, the present invention consists inthe devices and combinations of devices and method of op eration hereinafter described and more particularly defined in the claims. i

The invention in its preferred form is illustrated in the accompanying drawings in which Fig. -1- is a front elevation, partly in section, of the unit heating ventilator; Fig. 2 is a sectional 'view along the line 2 2 of Fig. 1 showing also the mode of installation of the unit heating ventilator; Fig. 3 is a side elevation of the unitventilator; Fig. 4 is a view of the thermo-regulating device in front elevation, and Fig. 5 in vertical section along the line 5-5 of Fig. 6'; Fig. 6 shows the device in side-elevation; Fig. 7 is a schematic diagram of the circulation of air within the unit heating" ventilator shown in 'a front elevation,

partly in section; and Fig. 8 is a side-elevation of a friction clamp utilized in a modification of the preferred embodiment of the invention.

The construction shown. in the drawings cmprises a ventilator casing'having suitable inlets 'for air,r neans of filtering the air, motor driven fans for forcing the air through the ventilator,

means for heating the air during its passage, means for by-passing the air' around the heating means, thermo-regulating means for actuating 'the means for by-passing the air around the heating means, and an outlet in the" casing for the emission of the air. v

In the ventilator illustrated in the drawings, a casing I contains heating elements 3 with extended surfaces over which currents of air are forced upwardly by the pair of squirrel cage fans 1 borne by and driven by the motor 9 mounted on the flexible suspensions II. The air so upwardly forced by the fans is drawn through the filter'l3 from the chamber I5 which is provided with two inlets. One, IT, of these inlets permits the passage into the chamber l5 of' the outdoor air from the usual duct or passage l9 through the wall 2|, while the other, 23, of the inlets permitsthe passage into the chamber [5 of the air of theroom wherein the unit heating ventilator is situated. I

The control of the admission of air through one inlet or the other is by means of a hand actuated damper 25, the spring ensemble 2! precluding any intermediate position of the damperand thereby preventing the possibility of the passage of air directly from the outdoors into the room. v

The filter I3 consists of along, shallow boxlike structure with wire netting forming its bottom and top, between which is held oily iron or steel fibres through which air passes fairly freely under the suction created by the fans.

The squirrel cage fans I are of the double intake type and have spiral casings 29 with inlet openings 31 at their sides and vertical tangential discharge through outlets 33 to the heating elements 3. I

For the purpose of controlling the amount of heat imparted to the air passing through the apparatus, two movable shutters or dampers 35 are provided, which are actuated by a thermoregulator shortly to be described. When the shutters are inthe positions shown in full lines in Fig. 2, all of the air from the fans passes over the heating elements 3 and the maximum heating effect is produced, but when the shutters are in the position shown in dotted lines in Figs. 2 and 3, all of the air from the fans is by-passed around the heating elements through the passage 3?, and the minimum, that is, substantially no heat whatsoever is imparted to the air. 1 In any intermediate position of dampers or shutters 35, a portion of the air passes over the heater and a portion is by-passed so that only a moderate amount of heating of the air discharged through the casing outlet 39 is effected. By proper adjustment of the shutters 35 any desired temperature of air can be obtained. s

The position of the shutters 35 is automatically controlled by thermostatic devices responsive to the temperature of the room wherein the heating ventilator is located. Heretofore such' devices have been located at some distance from the ven- "tilator and electrical or other connections have by reference to Figs. 4, 5 and 6. Briefly, it comprises a hermetically sealed metallic bellows 5| containing a substance such as ether, whose vapor pressure increases rapidly with the temperature and thereby expands the bellows. Through suitable connections between the bellows and the shutters, this expansion is effective to impart closing movements directly to the latter, while reverse movement is secured by means of a spring when the internal pressure decreases, following a reduction in temperature.

The bellows 5| of general elliptical cross-section as shown in dotted line in Fig. 4 and in full line in Fig. 5, is mounted within a box or chamber 53 secured to the end wall of the casing. Air may pass freely through the box or chamber from the air inlet grille 54 in the casing Wall, to and through the outlet 55 into the interior of the casing. The bellows is mounted in the chamber by means of a cage 51 having a back plate to engage thejbackof the bellows and supporting side straps 59 spaced around and extending from said plate with their free ends bent over and secured by screws 6| to the supporting plate 63 upon which the parts of the device are mounted and which in turn is secured to the end or side wall 65 of the casing by means of the screws 61.

Secured to the front face of the bellows structure by means of short posts 69 is the pressure plate ll of the same general elliptical shape as the bellows but slightly smaller. When the bellows expand, due to a rise in temperature and the vaporization of the ether or other liquid contained therein, the plate is pushed outwardly, that is, to the right as shown in Fig. 6, in opposition to the spring I3 and into a recess or opening in the supporting plate. Upon reduction of temperature, the spring forces the plate inwardly to collapse the bellows. The spring I3 rests at its inner end upon the bellows plate II and at its outer end upon the cross-head I5 having recesses at its top and bottom to receive the fixed horizontal posts or supports 'I'I integrally formed with the supporting plate 63 whereby the crosshead will be guided in its inward and outward movement. A hub or stem I9 on the cross-head holds the spring I3 from displacement.

The adjustment of the compression spring I3, in order to secure the operation of the regulator at the desired temperature, is obtained by means of the threaded stem 8| upon which the cross.- head is mounted. This stem carries the collar or shoulder 83 and is extended without threads through a bearing sleeve 85, terminating in a square end 81 to receive an adjusting key. The bearing is carried by a six-sided plate 89 secured to the ends of the posts 11. A screw 9I passing through the end wall 65 of the casing enters the extension 93 of the plate and affords additional support for the same and for the regulator.

The expanding and contracting movements of the bellows under the changes of temperature are transmitted to the shutters 35 to close and to open the same to a greater or less extent by means of the following mechanism. Secured to the bellows plate TI at each side of the compression spring 13 are the threaded studs 95, each having a horizontal V-notch at its outer end and with which engages the knife edge 91 on the bellcrank lever 99, actuating the same in, a counterclockwise direction, as viewed in Fig. 6, upon a rise in temperature and, outward movement of the stud. Positive movement in the reverse direction is imparted to the bell-crank lever by mean- .01 h n l plate lnl, having: its base plate I03 through which the stud 95 passes clamped between the adjusting nuts I05. This plate IIJI is provided at its front or right hand end, as viewed in Fig. 6, with a V-notch oppositely disposed to the V-notch on the end of the adjacent threaded stud, and in this V-notch' on the plate is a second knife edge on the bell-crank lever 99.

The above described arrangement of notches and knife edges is duplicated with the other threaded stud, so that the movements of the bellows plate will be imparted to the bell-crank lever without liability of tilting or binding of the plate or bellows or of the bell-crank lever. Thus the bell-crank lever will be positively actuated in one direction or the other upon changes in temperature and the consequent movement of the bellows to adjust the shutters 35.

The bell-crank lever 99 is composed of two parts, one part, indicated generally at I91, carrying the connections to the shutters, and the other part, which is indicated generally at I99, which is of irregular shape, bearing the knife edges and the supporting devices for the lever, the two parts being unitedbymeans of screws III.

The bearings for the irregular member I09 of the bell-crank lever comprise at one end a pivot pin H5 fixed in the bracket or projection H5 from the supporting plate 63, and at the other end a knife edge on the depending portion of the fixed angle bracket II,'l,:, whichengages with the notch on the" lever. portion of the bell-crank lever carries at: its; lower end the pivoted link H9, which in turn is connected at its lower end to the arm I2I, pivoted at one end upon the supporting plate 63 and connected at its other end to the closed spring I23, the upper end of which is adjustably connected to the fixed bracket I25. The action of the spring supports the bell-crank lever with its notch in,

engagement with the kniie edge on the bracket III, with the desired pressure determined by the adjustment of the spring, the spring expanding and contractingas required to permit movement of the bell-crank lever under the action of the bellows.

Motion from the free end of the bell-crank lever is transmitted to the shutters 35 by means of the link III- connected at its upper end to the arm I29 upon the; rock-shaft to which one of the shutters is attached, aseparate link connection IM to the-rock-shaft for the other shut-- ter causing simultaneous operation thereof.

In order to protect the regulator and its sensitive bellows from heatv and cold within the casing, an insulating lining I33- of: suitable material isapplied tothe inner wall ot the box or chamber 53., V a

To. permit hand control of the shutters, a handle I35v is provided, fixedupon the rockshaft ofoneotthe shutters, at the opposite end from the connection to. the regulator, and to insure the shutters being held in the desired adjusted position, there is provided the friction clamp. indicated generally at I91 and shown in detail in Fig. 8. During normal operation. of the apparatus,- while, the regulator is in control, the clamping members I39. are loosely held by the screws and nuts I4-I; so that little if any resistanceis offered. to movement of the, shaft by the; regulator. When; however). it: is. desired to control the shuttersby hand, the nuts, I: will be tightened: to; cause the; clamping members. to bear upon the. hub I.43.,-:on-,the=shaft withsufllrecirculated air 'mechanism, a more accurate and satisfactory regulation of the airdischargedby the ventijusted.

f Not only is the above described construction self-contained as to all its instrumentalities and 'controlsg-thus avoiding the installation of instruments and devices at some distance from the ventilator with pneumatic, electrical or other connections between the same, but by reason of the passage of a continuous small stream of over the damper lator into the room is secured and the liability of improper conditioning by reason of stagnated air or local currents at the particular location where the control instrument is placed is avoided. The mechanical connections between the damper and its controlling mechanism are accurate and positive, and being all located with in the casing, are protected from accidental injury or derangement.

The small continuous flowing stream of recirculated air is of such relatively small magnitude compared with the stream supplied by the fresh air inlet that even when the main recirculating inlet is closed and all the air is taken from the fresh air inlet, there is no appreciable effect upon the condition of the discharged air due to the addition of the small recirculated stream.

While the present invention has beenshown and described in what is now considered to be its preferred form, it is to be understood that it may be embodied in other constructions and arrangements.

Having thus described claimed is: a

l. A unit heating ventilator comprising a casthe invention, what is ing provided with a plurality of air inlets and an air oulet, one of the inlets admitting recirculated air at all times to the casing, a heating element, a fan for creating a flow of air through the inlets and the outlet, and devices located in the air stream entering said re-circulated. air inlet for controlling the temperature of the air stream discharged from the outlet independently of the flow of air through another of the air inlets.

2. A unit heating ventilator comprising a casing provided with a fresh air inlet and a re-circulating air inlet which admits re-circulated air to the casing at all times, an air outlet, a heating element, a thermo-regulator controlled by the temperature of the re-circulated air entering the inlet, and devices actuated by the regulator for varying the heating effect ofthe heating element independent of the flow of air through the fresh air inlet.

3. A unit heating ventilator comprising a casing provided with a fresh air inlet and a main and supplementary re-circulating air inlet, an air outlet, means for controlling the flow of air through the fresh air and the main re-circulating inlets, a heating element, means for creating a flow of air through the inlets and the outlet, and devices located within the casing and exposed solely to the stream of air entering the supplementary air inlet for controlling the temperatureof air emitted by the ventilator independently of the flow of air through the fresh air and the main recirculating inlets.

4. A unit heating ventilator comprising a casing provided with a plurality of air inlets and an air outlet, a motor and fan for causing the controlling flow of air through the casing, a heating ele- "ment in the casing with an air passage at the side thereof, a shutter for controlling the flow ofair over the heating element and through the air passage, and a thermo-regulator located within the casing and exposed to the air stream of the air inlets only for actuating the shutter to difierentially by-pass the air around the heating element for controlling the temperature of air emitted by the ventilator.

5. A unit heating ventilator comprising a casing provided with an air inlet and an air outlet, a motor and fan, a heating element an auxiliary air inlet, a supplementary chamber within the casing through which chamber the air from the auxiliary air inlet passes, a thermo-reg'ulator located in the chamber and exposed solely to the air entering the auxiliary air inlet, and means actuated by the regulator to control the temperature of the air discharged by the ventilator independently of the flow of air through the first mentioned air inlet.

6. A unit heating ventilator comprising a casing provided with a main air inlet and a supplementary air inlet which admits recirculated air to the casing at all times and with an air outlet, a heating element, means for controlling the heating effect thereof independently of the flow of air through the main air inlet, devices within the casing and exposed to the recirculated air stream and responsive to the temperature thereof, and positively acting connections between said devices and said means whereby the heating effect of the heating element is varied with variations in the temperature of the stream of recirculated air.

"I. A unit heating ventilator comprising a casing having main fresh air and recirculating air inlets, and a small supplementary recirculated air inlet, the volume of air admitted by such supplementary air inlet being insufficient to have appreciable effect upon the temperature of the air admitted by the main air inlet when united therewith, an air outlet, means for controlling the flow of air through the main inlets, a heating element, means for creating a flow of air through the main and supplementary inlets and outlet, and devices carried by the casing and exposed solely to the stream of air entering the supplementary air inlet for controlling the temperature of the air discharged from the outlet.

8. A unit heating ventilator comprising a casing having a main air inlet and a supplementary recirculated air inlet, a heating element, an air outlet, a pair of fans for creating a flow of air through the main and supplementary inlets and outlet, one fan handling the entire volume of air entering the supplementary air inlet and the other fan handling exclusivelythe' air entering the main airinlet, and devices carried by the casing and exposed solely to the stream of air entering the supplementary air inlet for control ling the temperature of the air discharged from the outlet.

9. Apparatus for conditioning air comprising a casing provided with a plurality of main air inlets and a supplementary recirculated air inlet, means for selectively controlling the main air inlets, an air outlet, a conditioning element, means for creating a flow of air through the main and supplementary inlets and outlet, and devices located within the casing and exposed solely to the stream of air entering the supplementary air inlet for controlling the operation of the conditioning element in accordance with the condition of the air entering the supplementary air inlet.

10. A paratus for conditioning air comprising a casing having a main air inlet and a supplementary recirculated air inlet, an air outlet, a conditioning element, means operating upon separate streams of air for creating a flow or air through the main and supplementary inlets and outlet, the casing being formed with air passages to conduct the entire volume of recirculated air entering through the supplementary air inlet into one of said separate streams, and devices a rie b he cas n d exp s o to h stream of recirculated air entering through the supplementary air inlet for controlling the condition of the air discharged from the outlet.

11. A unit heating ventilator comprising a casing having rnain fresh air and recirculating air inlets and a srnall supplementary recirculated air inlet, an air outlet, a double intake ian for reatin a fl w Q a r thmh th m in a d $1 1 plernentary inlets and outlet, the casing being orme w th ai pa sa o di th nt re 9 me o a r en e in he up m a y air in e on an ntake and qnly ir e n a ma air inlet to the other fan intake, a heating element, and devices carried by the casing and exposed sole y t t st m o i nt in the Supplementa y air n t for QQht l e th e perature of the air discharged from the outlet in a cordance with the mpe u e o e air entering the supplementary inlet.

7 CHARLES BRIDGES CERTIFICATE OF CORREGTEON.

Patent No. 2 006534. July 2, 1935.

CHARLES P. BRIDGES.

it is hereby certified that error appears in the printed speeificatien oi the above numbered patent requiring correction as follows: Page 3, first eelumn, line 41, claim 1, 0r "eulet" read outlet; and seeend eelnmn, line 6, claim 4, after "stream" insert the words of one; and line l3, claim 5, after "eiement" insert a eemma; and that the said Letters Patent shnuld be read with these corrections therein that the same may conform t0 the reeere oi the ease in the Patent Office. e

Signed and sealed this 20th day of August, A. l). 1935.

Leslie Frazer (Seal) Acting Cemmisslener ei Patents. 

